From patchwork Wed Sep 30 18:55:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Serge Semin X-Patchwork-Id: 11810081 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6A991618 for ; Wed, 30 Sep 2020 18:57:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 533FE20708 for ; Wed, 30 Sep 2020 18:57:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729980AbgI3S5A (ORCPT ); Wed, 30 Sep 2020 14:57:00 -0400 Received: from mail.baikalelectronics.com ([87.245.175.226]:41714 "EHLO mail.baikalelectronics.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730296AbgI3S4F (ORCPT ); Wed, 30 Sep 2020 14:56:05 -0400 Received: from localhost (unknown [127.0.0.1]) by mail.baikalelectronics.ru (Postfix) with ESMTP id 9756B803016F; Wed, 30 Sep 2020 18:55:59 +0000 (UTC) X-Virus-Scanned: amavisd-new at baikalelectronics.ru Received: from mail.baikalelectronics.ru ([127.0.0.1]) by localhost (mail.baikalelectronics.ru [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id o4aZ5pctNe7c; Wed, 30 Sep 2020 21:55:59 +0300 (MSK) From: Serge Semin To: Mark Brown CC: Serge Semin , Serge Semin , Alexey Malahov , Ramil Zaripov , Pavel Parkhomenko , Andy Shevchenko , Andy Shevchenko , Lars Povlsen , "wuxu . wu" , Feng Tang , Rob Herring , , , Subject: [PATCH v2 13/21] spi: dw: De-assert chip-select on reset Date: Wed, 30 Sep 2020 21:55:37 +0300 Message-ID: <20200930185545.29959-14-Sergey.Semin@baikalelectronics.ru> In-Reply-To: <20200930185545.29959-1-Sergey.Semin@baikalelectronics.ru> References: <20200930185545.29959-1-Sergey.Semin@baikalelectronics.ru> MIME-Version: 1.0 X-ClientProxiedBy: MAIL.baikal.int (192.168.51.25) To mail (192.168.51.25) Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org SPI memory operations implementation will require to have the CS register cleared before executing the operation in order not to have the transmission automatically started prior the Tx FIFO is pre-initialized. Let's clear the register then on explicit controller reset to fulfil the requirements in case of an error or having the CS left set by a bootloader or another software. Signed-off-by: Serge Semin --- drivers/spi/spi-dw.h | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/spi/spi-dw.h b/drivers/spi/spi-dw.h index cfc9f63acde4..eb1d46983319 100644 --- a/drivers/spi/spi-dw.h +++ b/drivers/spi/spi-dw.h @@ -237,15 +237,16 @@ static inline void spi_umask_intr(struct dw_spi *dws, u32 mask) } /* - * This disables the SPI controller, interrupts, clears the interrupts status, - * and re-enable the controller back. Transmit and receive FIFO buffers are - * cleared when the device is disabled. + * This disables the SPI controller, interrupts, clears the interrupts status + * and CS, then re-enables the controller back. Transmit and receive FIFO + * buffers are cleared when the device is disabled. */ static inline void spi_reset_chip(struct dw_spi *dws) { spi_enable_chip(dws, 0); spi_mask_intr(dws, 0xff); dw_readl(dws, DW_SPI_ICR); + dw_writel(dws, DW_SPI_SER, 0); spi_enable_chip(dws, 1); }